DESCRIPTION (Applicant's Abstract): Primary prevention through behavioral change remains the principal means of controlling the acquisition and spread of sexually-transmitted infections, most notably HIV. Although behavioral risk factors for sexually-transmitted diseases (STDs) are known, effective intervention strategies continue to be needed. Young women at risk for heterosexual acquisition or transmission of STDs are in particular need of effective intervention. Proposed is a randomized trial evaluating the effectiveness of a theory-based self-help behavior change intervention to increase condom use among young women at increased risk for heterosexually-transmitted HIV/STD. For this trial, 1,200 non-pregnant, sexually-active unmarried women 18-24 years of age will be recruited from two managed care sites: Group Health Cooperative of Puget Sound and Duke Family Medicine Clinic. Eligible women will be randomized to either a usual care control or to a tailored self-help intervention group. The intervention group will receive a self-help booklet addressing cognitive and behavioral factors associated with condom use along with a safer sex gift package and an introductory cover letter that has been tailored to their individual characteristics (as identified in a baseline survey). A booster tailored newsletter will be sent after the first follow-up survey. Control and intervention participants will be surveyed by telephone 2 and 6 months after randomization to assess changes in risk perception, self-efficacy and intentions to use condoms, and condom use. This randomized trial aims to develop and evaluate a behavior change intervention that, if proven effective, could be applied in a wide variety of health care settings.